The present invention relates to apparatus for separating compacted masses of vegetable material. More particularly, the invention relates to apparatus for delaminating tobacco compacted into "farmer's bales."
Tobacco marketing in the United States is a highly decentralized process. Typically, individual growers carry their tobacco to a local warehouse, where it is purchased by representatives of tobacco companies. Buyers consolidate their purchases for shipment to manufacturing facilities. Traditionally, consolidation has meant "prizing" the tobacco into hogsheads for shipment and future storage. This operation may take place in the local warehouse, if the warehouse is sufficiently large, but more typically it occurs in a "prize house," a facility devoted solely to that operation serving a number of warehouses in a region.
In the marketing of burley tobacco, two recent developments have upset the traditional pattern. First, buyers increasingly have abandoned the traditional hogshead in favor of the Tersa bale. In contrast to the round, wooden hogshead, the Tersa bale is formed by compressing about 1,100 pounds of tobacco into a cube, which optimizes transportation and storage. The bale is formed in a portable press, which is transported from market to market, and retained in its compressed state by straps. The resulting bale thus is self-supporting, without the necessity of a heavy burlap outer wrapper. A light overwrap, such as netting, may be used to prevent small pieces of tobacco from falling out of the bale.
The second development is the advent of the "farmer's bale" for burley tobacco. Traditionally, burley tobacco has been sold in "baskets," loose stacks of about 200-800 pounds of tobacco. The loose arrangement of the tobacco facilitated compression of several "baskets" into a Tersa bale. Recently, however, burley farmers have begun bringing their tobacco to market in "farmer's bales," as discussed in Duncan & Smiley, "Preparing Burley in Bales" (Univ. of Kentucky 1978). Such bales contain about 90 pounds of tobacco, but the tobacco is pressed into a bale one foot by two feet by three feet. As the tobacco is compressed into a relatively solid cake, these bales are considerably easier for farmers to handle. It is estimated that virtually all burley tobacco will be sold in this form within the near future.
As can be readily appreciated, the relatively solid farmer's bales do not lend themselves to formation of Tersa bales. Although farmer's bales do break down somewhat within the press, large lumps remain. The result is wide variations in density within the Tersa bale. For example, one test of a Tersa bale formed from farmer's bales showed that some portions of the Tersa bale were packed to a density of about ten pounds per cubic foot, while others ranged as high as 36 pounds per cubic foot. This phenomenon leads to poorly compacted Tersa bales. Because the Tersa bale depends upon compression to maintain its shape and integrity, the presence of such wide variations degrades the structural inegrity of the bale. Bales, particularly those upon which other bales are stacked, literally fall apart. When this occurs in shipment or storage, large amounts of tobacco are lost to wastage.
Buyers responded to the initial appearance of farmer's bales by resorting to hand separation of the bales prior to loading tobacco into the press. This solution was acceptable when farmer's bales constituted a small portion of the burley sold; obviously, the increase in usage of farmer's bales has led to the strong need for a mechanized, portable delamination apparatus.
The prior art offers little help in solving the problem of delaminating tightly compressed bales. Primarily, existing devices are directed toward the separation of rather loosely packed masses. For example, U.S. Pat. No. 2,873,747, to Schlossmacher, depends upon separating a tobacco bale by placing it upon an oscillating bed; vibration causes the leaves to separate from the bale. Further leaf separation is accomplished by passing the separated leaves through a succession of spiked wheels, whose spikes pass between sets of stationary spikes. This apparatus fails to solve the existing problem. First, farmer's bales do not fall apart when vibrated. Second, the combination of rotating and stationary spikes does not delaminate the farmer's bale but rather tears the bale into small pieces unacceptable at this stage of the tobacco processing. Also, this apparatus would produce an unacceptably high level of dust and fines. Furthermore, if the apparatus were modified to eliminate the stationary spikes, it was found that the rotating spiked wheel quickly became clogged with tobacco leaves, resulting in unacceptably high down time to clear the spikes. These disadvantages are shared by U.S. Pat. No. 1,328,734, to Harriss, another device using spiked wheels.
Another device, shown in U.S. Pat. No. 3,016,906, to Peters, discloses apparatus for separating tobacco lumps into individual particles by dropping lumps vertically into a chamber in which a plurality of yieldable projections are mounted. Flexing of the yieldable projections separates lumps into individual leaves for further processing. Again, this device is not adaptable to the problem of separating 90-pound bales. The bales simply do not separate readily in such a process.
The problem posed by compacted masses of tobacco can be seen dramatically in U. S. Pat. No. 3,838,698, to Dickenson. The solution presented there requires that a bale be forced onto a hollow probe, which passes moist air or steam into the bale, separating the lamina sufficiently so that tobacco can be separated by doffers. Although such a system may be effective, it also is expensive, requiring a supply of steam and rather cumbersome apparatus. Moreover, it utterly fails to meet the need for portable apparatus which may be transported between geographically dispersed tobacco markets.
Thus, the prior art leaves a tobacco buyer exactly where he started: no practical apparatus exists to eliminate the expensive hand separation of farmer's bales.